MS4A1-PTGS2 axis induces taurine metabolic reprogramming to exacerbate abdominal aortic aneurysm progression.

This study unveils the pivotal roles of taurine metabolic reprogramming and its implications in the development and progression of Abdominal Aortic Aneurysm (AAA). Leveraging an integrated approach that combines single-cell RNA sequencing (scRNA-seq) and Weighted Gene Co-expression Network Analysis (WGCNA), our research investigates the intricate transcriptional and gene expression dynamics crucial to AAA. Our findings uniquely link metabolic shifts to the integrity of the extracellular matrix (ECM) and the functionality of smooth muscle cells (SMCs), key elements in the pathology of AAA. Utilizing scRNA-seq data from a mouse model (GSE152583 dataset), we identified critical alterations in cellular composition during AAA progression, particularly highlighting shifts in fibroblasts and inflammatory cells. Concurrently, WGCNA of human AAA tissue samples has outlined distinct gene expression patterns correlated with disease severity and progression, offering comprehensive insights into both molecular and cellular disease mechanisms. Moreover, this study introduces innovative metabolic profiling techniques to identify differential metabolites in AAA, integrating extensive metabolomic analyses with pathway enrichment strategies. This novel approach has pinpointed potential biomarkers and therapeutic targets, notably within taurine metabolism pathways, crucial for crafting non-surgical interventions. By merging state-of-the-art bioinformatics with thorough molecular analysis, our study not only enhances the understanding of AAA's complex pathophysiology but also catalyzes the development of targeted therapeutic strategies. This research represents a significant advancement in the molecular characterization of AAA, with substantial implications for its future diagnosis and treatment strategies.

Suppressing appetite with taurine.

The taurine metabolite N-acetyltaurine protects mice from diet-induced obesity by reducing food intake.

Investigation of the Aggregation of Aß Peptide (1-40) in the Presence of κ-Carrageenan-Stabilised Liposomes Loaded with Homotaurine.

The kinetics of amyloid aggregation was studied indirectly by monitoring the changes in the polydispersity of mixed dispersion of amyloid ß peptide (1-40) and composite liposomes. The liposomes were prepared from the 1,2-dioleoyl-sn-glicero-3-phoshocholine (DOPC) phospholipid and stabilised by the electrostatic adsorption of κ-carrageenan. The produced homotaurine-loaded and unloaded liposomes had a highly negative electrokinetic potential and remarkable stability in phosphate buffer (pH 4 and 7.4). For the first time, the appearance and evolution of the aggregation of Aß were presented through the variation in the standard percentile readings (D10, D50, and D90) obtained from the particle size distribution analysis. The kinetic experiments indicated the appearance of the first aggregates almost 30 min after mixing the liposomes and peptide solution. It was observed that by adding unloaded liposomes, the size of 90% of the particles in the dispersion (D90) increased. In contrast, the addition of homotaurine-loaded liposomes had almost minimal impact on the size of the fractions of larger particles during the kinetic experiments. Despite the specific bioactivity of homotaurine in the presence of natural cell membranes, this study reported an additional inhibitory effect of the compound on the amyloid peptide aggregation due to the charge effects and 'molecular crowding'.

The association between taurine concentrations and dog characteristics, clinical variables, and diet in English cocker spaniels: The Canine taURinE (CURE) project.

BACKGROUND: Occurrence of low blood taurine concentrations (B-TauC) and predisposing factors to taurine deficiency in English Cocker Spaniels (ECS) are incompletely understood. OBJECTIVES: Investigate the occurrence of low B-TauC in a Swedish population of ECS and evaluate the association between B-TauC and dog characteristics, clinical variables, and diet composition. ANIMALS: One-hundred eighty privately owned ECS. METHODS: Dogs were prospectively recruited and underwent physical examination, blood analyses, and echocardiographic and ophthalmic examinations. Dogs with clinical signs of congestive heart failure (CHF) also underwent thoracic radiography. Taurine concentrations were analyzed in plasma (EDTA and heparin) and whole blood. Diets consumed by the dogs at the time of the examination were analyzed for dietary taurine- (D-TauC), cysteine- (D-CysC), and methionine concentrations (D-MetC). RESULTS: Fifty-three of 180 dogs (29%) had low B-TauC, of which 13 (25%) dogs had clinical and radiographic signs of CHF, increased echocardiographic left ventricular (LV) dimensions and volumes, and impaired LV systolic function. Five (9%) dogs with low B-TauC had retinal abnormalities. Dietary MetC, dietary animal protein source (red/white meat), and age were associated with B-TauC in the final multivariable regression model (P < .001, R2 adj = .39). CONCLUSIONS AND CLINICAL IMPORTANCE: Low B-TauC suggests that taurine deficiency may play a role in the development of myocardial failure and CHF in ECS. Low D-MetC and diets with red meat as the animal protein source were associated with low B-TauC. Dogs with B-TauC below the normal reference range were older than dogs with normal concentrations.

PTER is a N-acetyltaurine hydrolase that regulates feeding and obesity.

Taurine is a conditionally essential micronutrient and one of the most abundant amino acids in humans1-3. In endogenous taurine metabolism, dedicated enzymes are involved in the biosynthesis of taurine from cysteine and in the downstream metabolism of secondary taurine metabolites4,5. One taurine metabolite is N-acetyltaurine6. Levels of N-acetyltaurine are dynamically regulated by stimuli that alter taurine or acetate flux, including endurance exercise7, dietary taurine supplementation8 and alcohol consumption6,9. So far, the identities of the enzymes involved in N-acetyltaurine metabolism, and the potential functions of N-acetyltaurine itself, have remained unknown. Here we show that the body mass index associated orphan enzyme phosphotriesterase-related (PTER)10 is a physiological N-acetyltaurine hydrolase. In vitro, PTER catalyses the hydrolysis of N-acetyltaurine to taurine and acetate. In mice, PTER is expressed in the kidney, liver and brainstem. Genetic ablation of Pter in mice results in complete loss of tissue N-acetyltaurine hydrolysis activity and a systemic increase in N-acetyltaurine levels. After stimuli that increase taurine levels, Pter knockout mice exhibit reduced food intake, resistance to diet-induced obesity and improved glucose homeostasis. Administration of N-acetyltaurine to obese wild-type mice also reduces food intake and body weight in a GFRAL-dependent manner. These data place PTER into a central enzymatic node of secondary taurine metabolism and uncover a role for PTER and N-acetyltaurine in body weight control and energy balance.

Taurine Deficiency Is a Hallmark of Injured Kidney Allografts.

BACKGROUND: Taurine is one of the most abundant amino acids in humans. Low taurine levels are associated with cellular senescence, mitochondrial dysfunction, DNA damage, and inflammation in mouse, all of which can be reversed by supplementation. It is unknown whether taurine metabolism is associated with kidney allograft function and survival. METHODS: We performed urine metabolomic profiling of kidney transplant recipients in the early and late phases after transplantation combined with transcriptomic analysis of human kidney allografts. Single-nucleus RNA sequencing data sets of mouse kidneys after ischemia-reperfusion injury were analyzed. We analyzed the association of urinary taurine levels and taurine metabolism genes with kidney function, histology, and graft survival. RESULTS: Urine taurine concentrations were significantly lower in kidney transplant recipients who experienced delayed graft function. In a mouse model of ischemia-reperfusion injury, the taurine biosynthesis gene, CSAD , but not the taurine transporter SLC6A6 , was repressed. In the late stage of transplantation, low level of taurine in urine was associated with impaired kidney function and chronic structural changes. Urine taurine level in the lowest tertile was predictive of graft loss. Expression of the taurine transporter SLC6A6 in the upper median, but not CSAD , was associated with chronic kidney injury and was predictive of graft loss. CONCLUSIONS: Low urine taurine level is a marker of injury in the kidney allograft, is associated with poor kidney function, is associated with chronic histological changes, and is predictive of graft survival. The differential expression of CSAD and SLC6A6 , depending on the time after transplantation and marks of injury, highlights different mechanisms affecting taurine metabolism.

Mitigation of aging-related plasticity decline through taurine supplementation and environmental enrichment.

Aging-related biochemical changes in nerve cells lead to dysfunctional synapses and disrupted neuronal circuits, ultimately affecting vital processes such as brain plasticity, learning, and memory. The imbalance between excitation and inhibition in synaptic function during aging contributes to cognitive impairment, emphasizing the importance of compensatory mechanisms. Fear conditioning-related plasticity of the somatosensory barrel cortex, relying on the proper functioning and extensive up regulation of the GABAergic system, in particular interneurons containing somatostatin, is compromised in aging (one-year-old) mice. The present research explores two potential interventions, taurine supplementation, and environmental enrichment, revealing their effectiveness in supporting learning-induced plasticity in the aging mouse brain. They do not act through a mechanism normalizing the Glutamate/GABA balance that is disrupted in aging. Still, they allow for increased somatostatin levels, an effect observed in young animals after learning. These findings highlight the potential of lifestyle interventions and diet supplementation to mitigate age-related cognitive decline by promoting experience-dependent plasticity.

Long-Term Stability and Efficacy of NCT Solutions.

To realize the potential for the use of N-chlorotaurine (NCT) in healthcare, a better understanding of the long-term stability of the compound in water is needed. An array of analytical procedures is required that can measure changes in NCT concentration over time and allow for the detection and identification of contaminants and likely degradation end products. We used UV-Vis and NMR spectroscopy, HPLC, and LCMS to establish the stability of NCT in solutions subjected to prolonged ambient and elevated temperatures. Stability proved to be dependent on concentration with half-lives of ~120 days and ~236 days for 1% and 0.5% solutions of NCT at ~20 °C. Regardless of initial pH, all solutions shifted toward and maintained a pH of ~8.3 at 20 °C and 40 °C. NCT at 500 µg/mL and 250 µg /mL inhibited biofilm formation by Pseudomonas aeruginosa and Staphylococcus aureus but did not disperse established biofilms. NCT exposure to the biofilms had profound effects on the viability of both bacteria, reducing live organisms by >90%. Exposure of Interleukin-6 (IL-6) to 11 µM NCT reduced the binding of IL-6 to an immobilized specific antibody by ~48%, which is 5× the amount required for HOCl to bring about the same effect in this test system. Our data demonstrate the potency of the compound as an antimicrobial agent with potential benefits in the management of infected chronic wounds and suggest that NCT may contribute to anti-inflammatory processes in vivo by direct modification of cytokine mediators.

Insights into the cardiovascular benefits of taurine: a systematic review and meta-analysis.

BACKGROUND: Cardiovascular disease (CVD) remains the foremost cause of mortality globally. Taurine, an amino acid, holds promise for cardiovascular health through mechanisms such as calcium regulation, blood pressure reduction, and antioxidant and anti-inflammatory effects. Despite these potential benefits, previous studies have yielded inconsistent results. This meta-analysis of randomized controlled trials (RCTs) aims to evaluate the existing evidence on the quantitative effects of taurine on hemodynamic parameters and cardiac function grading, which are indicative of overall cardiovascular health and performance. METHODS: We conducted an electronic search across multiple databases, including Embase, PubMed, Web of Science, Cochrane CENTRAL, and ClinicalTrials.gov, from their inception to January 2, 2024. Our analysis focused on key cardiovascular outcomes, such as heart rate (HR), systolic blood pressure (SBP), diastolic blood pressure (DBP), left ventricular ejection fraction (LVEF), and New York Heart Association (NYHA) Functional Classification. Meta-regression was applied to explore dose-dependent relationships based on the total taurine dose administered during the treatment period. A subgroup analysis, stratified according to the baseline disease status of patients, was also conducted. RESULTS: The analysis included a pooled sample of 808 participants from 20 randomized controlled trials. Taurine demonstrated a significant reduction in HR (weighted mean difference [WMD] = -3.579 bpm, 95% confidence interval [CI] = -6.044 to -1.114, p = 0.004), SBP (WMD = -3.999 mm Hg, 95% CI = -7.293 to -0.706, p = 0.017), DBP (WMD: -1.435 mm Hg, 95% CI: -2.484 to -0.386, p = 0.007), NYHA (WMD: -0.403, 95% CI: -0.522 to -0.283, p < 0.001), and a significant increase in LVEF (WMD: 4.981%, 95% CI: 1.556 to 8.407, p = 0.004). Meta-regression indicated a dose-dependent reduction in HR (coefficient = -0.0150 per g, p = 0.333), SBP (coefficient = -0.0239 per g, p = 0.113), DBP (coefficient = -0.0089 per g, p = 0.110), and NYHA (coefficient = -0.0016 per g, p = 0.111), and a positive correlation with LVEF (coefficient = 0.0285 per g, p = 0.308). No significant adverse effects were observed compared to controls. In subgroup analysis, taurine significantly improved HR in heart failure patients and healthy individuals. Taurine significantly reduced SBP in healthy individuals, heart failure patients, and those with other diseases, while significantly lowered DBP in hypertensive patients It notably increased LVEF in heart failure patients and improved NYHA functional class in both heart failure patients and those with other diseases. CONCLUSIONS: Taurine showed noteworthy effects in preventing hypertension and enhancing cardiac function. Individuals prone to CVDs may find it advantageous to include taurine in their daily regimen.

N-Chlorotaurine Solutions as Agents for Infusion Detoxification Therapy: Preclinical Studies.

N-chlorotaurine (NCT) is a broad-spectrum antimicrobial agent with outstanding tolerability, effective for topical and inhalation use. This paper presents the results of studies of single and repeated intravenous infusions of NCT to laboratory animals. The studies were conducted on female Wistar Han rats. The effect of NCT infusions on the general condition, behavioral reactions, main biochemical and hematological parameters, hemocoagulation system, cardiovascular system, and on the condition of the internal organs was studied. It was found that NCT infusions do not reveal deviations in the studied parameters that could indicate a toxic effect. The estimated LD50 is more than 80 mg/kg. In a subchronic experiment, a statistically significant decrease in cholesterol (by up to 11%), glucose (by up to 15%) and excess bases (up to four times) in the blood, and an increase in heart rate (by up to 31%) and frequency of defecations (by up to 35%), as well as pronounced antiplatelet effect, were found. In animals with simulated endotoxicosis, a decrease in the cytolysis and oxidative stress markers was observed. Such effects are caused by both chlorine-active compounds and taurine.The results obtained indicate broad prospects for the use of NCT solutions as an infusion detoxifying agent.

Activity of N-Chlorotaurine against Periodontal Pathogens.

Dental plaque bacteria play an important role in the pathogenicity of periodontitis and peri-implantitis. Therefore, antimicrobial agents are one means of treatment. N-chlorotaurine (NCT) as an endogenous well-tolerated topical antiseptic could be of advantage for this purpose. Accordingly, its microbicidal activity against some dental plaque bacteria was investigated at therapeutic concentrations in vitro. In quantitative killing assays, the activity of NCT against planktonic bacteria and against biofilms grown for 48 h on implantation screws was tested. Electron microscopy was used to demonstrate the formation of biofilm and its morphological changes. The killing of planktonic bacteria of all tested species, namely Streptococcus sanguinis, Streptococcus salivarius, Streptococcus oralis, Streptococcus cristatus, Rothia aeria, and Capnocytophaga ochracea, was shown within 10-20 min by 1% NCT in 0.01 M phosphate-buffered saline at 37 °C. Bacteria grown on screws for 24 h were inactivated by 1% NCT after 15-20 min as well, but the formation of biofilm on the screws was visible in electron microscopy not before 48 h. The killing of biofilms by 1% NCT was demonstrated after 30 min (streptococci) and 40 min (R. aeria). As expected, NCT has broad activity against dental plaque bacteria as well and should be further investigated on its clinical efficacy in periodontitis and peri-implantitis.

Taurine, alpha lipoic acid and vitamin B6 ameliorate the reduced developmental competence of immature mouse oocytes exposed to methylglyoxal.

Advanced glycation end products (AGEs) are the final products of the Maillard reaction, formed through the interaction of carbohydrates and proteins. Reactive dicarbonyl compounds such as methylglyoxal (MGO) serve as precursors for AGEs formation. Elevated levels of MGO/AGEs are observed in conditions like obesity, polycystic ovarian syndrome (PCOS), and diabetes, negatively impacting oocyte development. Previous studies have shown that hydrogen sulfide, a gasotransmitter with anti-AGEs effects, is produced in a process influenced by vitamin B6. R-α-lipoic acid (ALA) inhibits protein glycation and AGEs formation while stimulating glutathione (GSH) production. Taurine mitigates oxidative stress and acts as an anti-glycation compound, preventing in vitro glycation and AGEs accumulation. This study aimed to explore the ameliorative effects of a micronutrient support (Taurine, ALA and B6: TAB) on mouse oocytes challenged with MGO. Our results indicate that MGO reduces oocyte developmental competence, while TAB supplementation improves maturation, fertilization, and blastocyst formation rates. TAB also restores cell lineage allocation, redox balance and mitigates mitochondrial dysfunction in MGO-challenged oocytes. Furthermore, cumulus cells express key enzymes in the transsulfuration pathway, and TAB enhances their mRNA expression. However, TAB does not rescue MGO-induced damage in denuded oocytes, emphasizing the supportive role of cumulus cells. Overall, these findings suggest that TAB interventions may have significant implications for addressing reproductive dysfunctions associated with elevated MGO/AGEs levels. This study highlights the potential of TAB supplementation in preserving the developmental competence of COCs exposed to MGO stress, providing insights into mitigating the impact of dicarbonyl stress on oocyte quality and reproductive outcomes.

1ß-Hydroxydeoxycholic Acid as an Endogenous Biomarker in Human Plasma for Assessment of CYP3A Clinical Drug-Drug Interaction Potential.

4ß-Hydroxycholesterol (4ß-HC) in plasma has been used as a biomarker to assess CYP3A drug-drug interaction (DDI) potential during drug development. However, due to the long half-life and narrow dynamic range of 4ß-HC, its use has been limited to the identification of CYP3A inducers, but not CYP3A inhibitors. The formation of 1ß-hydroxydeoxycholic acid (1ß-OH DCA) from deoxycholic acid (DCA) is mediated by CYP3A, thus 1ß-OH DCA can potentially serve as an alternative to 4ß-HC for assessment of CYP3A DDI potential. To study this feasibility, we developed a sensitive liquid chromatography-tandem mass spectrometry method for the simultaneous quantitation of 1ß-OH DCA and its glycine and taurine conjugates in human plasma with the lower limit of quantitation of 50 pg/ml, which enabled the quantitation of basal levels and further reduction. The method was applied to a DDI study to assess how 1ß-OH DCA and its glycine and taurine conjugates would respond to CYP3A induction or inhibition. Rifampin induction resulted in an increase of 1ß-OH DCA and its conjugates in plasma, with 6.8-, 7.8-, 8.3-, and 10.3-fold increases of area under the curve from the time of dosing to the last measurable concentration (AUCLST), area under the curve from the time of dosing to 24 hours (AUC24h), C max, and mean concentrations for total 1ß-OH DCA (total of all three forms), respectively. Importantly, inhibition with itraconazole resulted in notable reduction of these biomarkers, with 84%, 85%, 82%, and 81% reductions of AUCLST, AUC24h, C max, and mean concentrations for total 1ß-OH DCA, respectively. These preliminary data demonstrate for the first time that total 1ß-OH DCA in plasma has the potential to serve as a biomarker for CYP3A DDI assessment in early clinical development and may provide key advantages over 4ß-HC. SIGNIFICANCE STATEMENT: The authors have reported the use of total 1ß-hydroxydeoxycholic acid (1ß-OH DCA) (sum of 1ß-OH DCA and its glycine and taurine conjugates) plasma exposure as a biomarker for CYP3A activity. Itraconazole inhibition led to an 81%-85% decrease of total 1ß-OH DCA plasma exposures, whereas rifampin induction led to a 6.8- to 10.3-fold increase of total 1ß-OH DCA plasma exposures. Using 1ß-OH DCA exposures in plasma also provides the benefit of allowing pharmacokinetic and biomarker assessment using the same matrix.

Altered brain metabolites in male nonhuman primate offspring exposed to maternal immune activation.

Converging data show that exposure to maternal immune activation (MIA) in utero alters brain development in animals and increases the risk of neurodevelopmental disorders in humans. A recently developed non-human primate MIA model affords opportunities for studies with uniquely strong translational relevance to human neurodevelopment. The current longitudinal study used 1H-MRS to investigate the developmental trajectory of prefrontal cortex metabolites in male rhesus monkey offspring of dams (n = 14) exposed to a modified form of the inflammatory viral mimic, polyinosinic:polycytidylic acid (Poly IC), in the late first trimester. Brain metabolites in these animals were compared to offspring of dams that received saline (n = 10) or no injection (n = 4). N-acetylaspartate (NAA), glutamate, creatine, choline, myo-inositol, taurine, and glutathione were estimated from PRESS and MEGA-PRESS acquisitions obtained at 6, 12, 24, 36, and 45 months of age. Prior investigations of this cohort reported reduced frontal cortical gray and white matter and subtle cognitive impairments in MIA offspring. We hypothesized that the MIA-induced neurodevelopmental changes would extend to abnormal brain metabolite levels, which would be associated with the observed cognitive impairments. Prefrontal NAA was significantly higher in the MIA offspring across all ages (p < 0.001) and was associated with better performance on the two cognitive measures most sensitive to impairment in the MIA animals (both p < 0.05). Myo-inositol was significantly lower across all ages in MIA offspring but was not associated with cognitive performance. Taurine was elevated in MIA offspring at 36 and 45 months. Glutathione did not differ between groups. MIA exposure in male non-human primates is associated with altered prefrontal cortex metabolites during childhood and adolescence. A positive association between elevated NAA and cognitive performance suggests the hypothesis that elevated NAA throughout these developmental stages reflects a protective or resilience-related process in MIA-exposed offspring. The potential relevance of these findings to human neurodevelopmental disorders is discussed.

Exploring the effects of taurolidine on tumor weight and microvessel density in a murine model of osteosarcoma.

Background: Osteosarcoma is the most common malignant primary bone tumor. The prognosis for patients with disseminated disease remains very poor despite recent advancements in chemotherapy. Moreover, current treatment regimens bear a significant risk of serious side effects. Thus, there is an unmet clinical need for effective therapies with improved safety profiles. Taurolidine is an antibacterial agent that has been shown to induce cell death in different types of cancer cell lines. Methods: In this study, we examined both the antineoplastic and antiangiogenic effects of taurolidine in animal models of osteosarcoma. K7M2 murine osteosarcoma cells were injected, both intramuscular and intraperitoneal, into 60 BALB/c mice on day zero. Animals were then randomized to receive treatment with taurolidine 2% (800 mg/kg), taurolidine 1% (400 mg/kg), or NaCl 0.9% control for seven days by intravenous or intraperitoneal administration. Results: After 35 days, mice were euthanized, and the tumors were harvested for analysis. Eighteen mice were excluded from the analysis due to complications. Body weight was significantly lower in the 2% taurolidine intraperitoneal treatment group from day 9 to 21, consistent with elevated mortality in this group. Intraperitoneal tumor weight was significantly lower in the 1% (p = 0.003) and 2% (p = 0.006) intraperitoneal taurolidine treatment groups compared to the control. No antineoplastic effects were observed on intramuscular tumors or for intravenous administration of taurolidine. There were no significant differences in microvessel density or mitotic rate between treatment groups. Reduced body weight and elevated mortality in the 2% taurolidine intraperitoneal group suggest that the lower 1% dose is preferable. Conclusions: In conclusion, there is no evidence of antiangiogenic activity, and the antitumor effects of taurolidine on osteosarcoma observed in this study are limited. Moreover, its toxic profile grants further evaluation. Given these observations, further research is necessary to refine the use of taurolidine in osteosarcoma treatment.

Role of sulfidogenic members of the gut microbiota in human disease.

The human gut flora comprises a dynamic network of bacterial species that coexist in a finely tuned equilibrium. The interaction with intestinal bacteria profoundly influences the host's development, metabolism, immunity, and overall health. Furthermore, dysbiosis, a disruption of the gut microbiota, can induce a variety of diseases, not exclusively associated with the intestinal tract. The increased consumption of animal protein, high-fat and high-sugar diets in Western countries has been implicated in the rise of chronic and inflammatory illnesses associated with dysbiosis. In particular, this diet leads to the overgrowth of sulfide-producing bacteria, known as sulfidogenic bacteria, which has been linked to inflammatory bowel diseases and colorectal cancer, among other disorders. Sulfidogenic bacteria include sulfate-reducing bacteria (Desulfovibrio spp.) and Bilophila wadsworthia among others, which convert organic and inorganic sulfur compounds to sulfide through the dissimilatory sulfite reduction pathway. At high concentrations, sulfide is cytotoxic and disrupts the integrity of the intestinal epithelium and mucus barrier, triggering inflammation. Besides producing sulfide, B. wadsworthia has revealed significant pathogenic potential, demonstrated in the ability to cause infection, adhere to intestinal cells, promote inflammation, and compromise the integrity of the colonic mucus layer. This review delves into the mechanisms by which taurine and sulfide-driven gut dysbiosis contribute to the pathogenesis of sulfidogenic bacteria, and discusses the role of these gut microbes, particularly B. wadsworthia, in human diseases.

Copper Is Accumulated as Copper Sulfide Particles, and Not Bound to Glutathione, Phytochelatins or Metallothioneins, in the Marine Alga Ulva compressa (Chlorophyta).

To analyze the mechanism of copper accumulation in the marine alga Ulva compressa, it was cultivated with 10 µM of copper, with 10 µM of copper and increasing concentrations of a sulfide donor (NaHS) for 0 to 7 days, and with 10 µM of copper and a concentration of the sulfide acceptor (hypotaurine) for 5 days. The level of intracellular copper was determined as well as the level of glutathione (GSH) and phytochelatins (PCs) and the expression of metallothioneins (UcMTs). The level of intracellular copper in the algae treated with copper increased at day 1, slightly increased until day 5 and remained unchanged until day 7. The level of copper in the algae cultivated with copper and 100 or 200 µM of NaHS continuously increased until day 7 and the copper level was higher in the algae cultivated with 200 µM of NaHS compared to 100 µM of NaHS. In contrast, the level of intracellular copper decreased in the algae treated with copper and hypotaurine. The level of intracellular copper did not correlate with the level of GSH or with the expression of UcMTs, and PCs were not detected in response to copper, or copper and NaHS. Algae treated with copper and with copper and 200 µM of NaHS for 5 days were visualized by TEM and the elemental composition of electrondense particles was analyzed by EDXS. The algae treated with copper showed electrondense particles containing copper and sulfur, but not nitrogen, and they were mainly located in the chloroplast, but also in the cytoplasm. The algae treated with copper and NaHS showed a higher level of electrondense particles containing copper and sulfur, but not nitrogen, and they were located in the chloroplast, and in the cytoplasm. Thus, copper is accumulated as copper sulfide insoluble particles, and not bound to GSH, PCs or UcMTs, in the marine alga U. compressa.

[Substance abuse and cardiovascular risk: energy drinks]. / Sostanze d'abuso e rischio cardiovascolare: gli energy drinks.

The consumption of energy drinks (ED) has become a growing public health issue, since potentially ED-related serious adverse cardiovascular events, including arrhythmias, myocardial infarction, cardiomyopathies, and sudden cardiac death, have been reported in recent years. The substances contained in ED include caffeine, taurine, sugars, B group vitamins and phyto-derivatives, which, especially if taken in large quantities and in a short amount of time, could cause serious side effects through various mechanisms of action, such as increased blood pressure and QT interval prolongation. Although there are still many open questions on ED that require further specific investigations, there is an urgent need for information and educational plans to the population, as well as for regulatory actions, particularly regarding transparency of substances and possible adverse effects.

Taurine modulates host cell responses to Helicobacter pylori VacA toxin.

Colonization of the human stomach with Helicobacter pylori strains producing active forms of the secreted toxin VacA is associated with an increased risk of peptic ulcer disease and gastric cancer, compared with colonization with strains producing hypoactive forms of VacA. Previous studies have shown that active s1m1 forms of VacA cause cell vacuolation and mitochondrial dysfunction. In this study, we sought to define the cellular metabolic consequences of VacA intoxication. Untargeted metabolomic analyses revealed that several hundred metabolites were significantly altered in VacA-treated gastroduodenal cells (AGS and AZ-521) compared with control cells. Pathway analysis suggested that VacA caused alterations in taurine and hypotaurine metabolism. Treatment of cells with the purified active s1m1 form of VacA, but not hypoactive s2m1 or Δ6-27 VacA-mutant proteins (defective in membrane channel formation), caused reductions in intracellular taurine and hypotaurine concentrations. Supplementation of the tissue culture medium with taurine or hypotaurine protected AZ-521 cells against VacA-induced cell death. Untargeted global metabolomics of VacA-treated AZ-521 cells or AGS cells in the presence or absence of extracellular taurine showed that taurine was the main intracellular metabolite significantly altered by extracellular taurine supplementation. These results indicate that VacA causes alterations in cellular taurine metabolism and that repletion of taurine is sufficient to attenuate VacA-induced cell death. We discuss these results in the context of previous literature showing the important role of taurine in cell physiology and the pathophysiology or treatment of multiple pathologic conditions, including gastric ulcers, cardiovascular disease, malignancy, inflammatory diseases, and other aging-related disorders.

The transcription factors HNF-4α and NF-κB activate the CDO gene to promote taurine biosynthesis in the golden pompano Trachinotus ovatus (Linnaeus 1758).

Cysteine dioxygenase (CDO) is a rate-limiting enzyme in taurine biosynthesis. Taurine synthesis is limited in marine fish, and most taurine is provided by their diet. Although a nutritional study indicated that the transcription of ToCDO was significantly altered by treatment with 10.5 g/kg taurine in food, the regulatory mechanism of this biosynthesis has not been fully elucidated. In the present study, we identified the sequence features of Trachinotus ovatus cysteine dioxygenase (ToCDO), which consists of 201 amino acids. It is characterized by being a member of the cupin superfamily with two conserved cupin motifs located at amino acids 82-102 and 131-145 and with a glutamate residue substituted by a cysteine in its first motif. Moreover, phylogenetic analysis revealed that the similarity of the amino acid sequences between ToCDO and other species ranged from 84.58 % to 91.54 %. Furthermore, a high-performance liquid-phase assay of the activity of recombinantly purified ToCDO protein showed that ToCDO could catalyse the oxidation of cysteine to produce cysteine sulphite. Furthermore, the core promoter region of CDO was identified as -1182-+1 bp. Mutational analysis revealed that the HNF4α and NF-κB sites significantly and actively affected the transcription of CDO. To further investigate the binding of these two loci to the CDO promoter, an electrophoretic shift assay (EMSA) was performed to verify that HNF4α-1 and NF-κB-1 interact with the binding sites of the promoter and promote CDO gene expression, respectively. Additionally, cotransfection experiments showed that HNF4α or both HNF4α and NF-κB can significantly influence CDO promoter activity, and HNF4α was the dominant factor. Thus, HNF4α and NF-κB play important roles in CDO expression and may influence taurine biosynthesis within T. ovatus by regulating CDO expression.